“…North American literature shows that combining trauma registry data with pre-hospital deaths (coroner's department or medical examiner's data [ 91 - 93 ]) allows computation of major trauma death and morbidity rates. Some others authors use questionnaires to collect information on socio-demographic characteristics of the patient and injury details in studies of children under treatment or admitted to a hospital [ 76 ], patients admitted to a hospital and a sample of patients treated by general practitioners [ 81 ], or children treated at an emergency department only [ 58 , 75 ]. Questionnaires of self-reported illness as a primary data source have the advantage that the items to be collected can be tailored to specific research questions, but are time consuming to administer and usually involve smaller sample size compared to secondary data (data collected by people other than the researcher in question, for example, public vital statistics records).…”